Optimizing diagnosis, staging, and management of gastrointestinal stromal tumors

Neoadjuvant Imatinib in Gastrointestinal Stromal Tumors (GIST): The First Analysis of a Mexican Population

Introduction Gastrointestinal stromal tumors (GISTs) are neoplasms originating from the interstitial cells of Cajal, pacemaker cells responsible for intestinal motility. Patients with locally advanced GISTs and those with borderline resections due to the proximity of vital anatomical structures, which could result in unacceptable post-surgical morbidity, require special therapeutic consideration. Imatinib, a tyrosine kinase inhibitor, has demonstrated significant success in the non-surgical management of metastatic GIST, and its favorable impact on overall survival in the adjuvant setting makes it logical to speculate on the benefit it could provide as a neoadjuvant medication in patients with locally advanced disease. Methods Patients aged 18-90 years with a diagnosis of GIST confirmed by immunohistochemistry (CD117 positivity) who were treated at the Oncology Hospital of Centro Médico Nacional Siglo XXI in Mexico City from January 2012 to December 2016 were included in the study. It is a retrospective study with a duration of four years. Clinical data were collected from the medical records, which included sex, age, tumor location, initial resectability, reason for unresectability, initial tumor size, and mitotic rate. In the case of unresectable disease, patients who were evaluated by medical oncology and who had received treatment with 400 mg of imatinib daily were evaluated. Results A total of 312 patients diagnosed with GIST were analyzed. One hundred thirty-one were men (42%) with a mean age of 57 years, and 181 were women (58%) with a mean age of 59 years. The most frequent anatomical location was the stomach (n=185, 59.2%). At the time of diagnosis, 210 patients (67.3%) presented with resectable disease, while n=102 patients (32.7%) had unresectable disease. A total of 102 patients with unresectable disease received therapy with 400 mg of imatinib per day. Sixteen patients (15.7%) presented a reduction in tumor dimensions and underwent surgery. Conclusion The study highlights the importance of complete surgical resection and the potential benefit of neoadjuvant imatinib therapy in converting unresectable to resectable disease. The results suggest that imatinib can be effective in converting unresectable GISTs to resectable ones, allowing for a complete resection to be performed and obtaining an R0 resection in 93.7% of these cases.

A gist on an obscure neoplasm in Ghana: gastrointestinal stromal tumours

BACKGROUND

Gastrointestinal Stromal Tumour is a rare but potentially curable tumour of the gastrointestinal tract accounting for up to 1% of all gastrointestinal tumours. The discovery of Imatinib mesylate, a novel tyrosine kinase inhibitor has improved the chances even for unresectable, recurrent, or metastatic diseases.

METHODS

This study sought to document the clinical and pathological characteristics of GISTs from two tertiary hospitals in Ghana that have undergone immunohistochemistry confirmation between 2014 and 2021.

RESULTS

The median age of the subjects was 50 years with most of them (28.0%) being above 61 years. There were more females than males (64.0% vs. 36.0%). Abdominal mass and abdominal pain made up the majority of the clinical presentations. The majority of the subjects had partial gastrectomy (32.0%) which was followed by wedge resection (28.0%). Appendectomy and sleeve gastrectomy were the least performed procedures (8% each). Four of the 25 patients (16.0%) had resections of involved contiguous organs done with splenectomy being the most common procedure. The majority of GISTs were found in the stomach (68.0%) followed by the appendix (12.0%) and small bowel (12.0%). Gastrointestinal bleeding (55.8%) and abdominal pain (38.5%) were the most reported symptoms. Free resection margins were observed in 84.0% of the subjects and only 3/25 (12.0%) experienced tumour recurrence.

CONCLUSION

GIST is a potentially curable tumour that once was obscure but currently gaining popularity. Surgical resection offers the hope of a cure for localized disease while targeted therapies is a viable option for recurrent, metastatic, or unresectable tumours.

Unusual presentation of a large GIST in an extraintestinal site: a challenging diagnosis dilemma

Gastrointestinal stromal tumour (GIST) is a recent recognised tumour entity. In the past, those tumours were classified as leiomyomas, leiomyosarcomas and leiomyoblastomas, but it is now evident that GIST is a separate tumour entity and is the most common sarcoma of the gastrointestinal tract especially with advances in immunohistochemical staining techniques and improvements in microscopic structural imaging. We present a case of GIST of unusual location and presentation pattern, with an overview over current GISTs' diagnosis and management strategies. The precise incidence and tumour behaviour of rare extragastrointestinal stromal tumour (EGIST) remain to be clarified. Further research is needed in large series with long duration of follow-up and modified risk stratification assessment tailored for EGISTs.

Laparoscopic Versus Open Resection for Gastric Gastrointestinal Stromal Tumors (GISTs): A Size-Location-Matched Case-Control Study

BACKGROUND

Laparoscopic resection for gastric gastrointestinal stromal tumors (GISTs) is technically feasible, but the long-term effect remains uncertain. This study aims to compare the long-term oncologic outcomes of laparoscopic versus open resection of GISTs by larger cases based on tumor size-location-matched study.

METHODS

Between 2006 and 2015, 63 consecutive patients with a primary gastric GIST undergoing laparoscopic resection were enrolled in and matched (1:1) to patients undergoing open resection by tumor size and location. Clinical and pathologic parameters and surgical outcomes associated with each surgical type were collected and compared.

RESULTS

The operation time, intraoperative blood loss, return of bowel function and oral intake, nasogastric tube retention time and postoperative stay were all shorter/faster in laparoscopic group than those in open group (P < 0.001). Postoperative complications were comparable except for the higher incidence of abdominal/incision pain in open group (9.52 vs 27%, P = 0.01). There was no statistical difference in recurrence rate (9.52 vs 15.87%, P = 0.29) and long-term recurrence-free survival between the two groups (P = 0.39).

CONCLUSIONS

The long-term oncologic outcome of laparoscopic resection of primary gastric GISTs is comparable to that of open procedure, but laparoscopic procedure has the advantage of minimal invasion and is superior in postoperative recovery.

Challenging Diagnosis of Ileal Gastrointestinal Stromal Tumor Presenting with Obscure Digestive Bleeding

We report a case of a patient observed in emergency condition for recurrent episodes of massive obscure gastrointestinal bleeding that required surgical control. At laparotomy we found an ileal mass with the characteristics of a gastrointestinal stromal tumor (GIST) at histopathological analysis. GISTs should always be considered as a possible cause of obscure gastrointestinal bleeding, although they are often difficult to diagnose preoperatively. Laparotomy is sometimes the only way to obtain a diagnosis. Starting from this case, we reviewed the literature about GISTs, focusing our attention on their diagnosis and the possible surgical and nonsurgical therapies.

How best to manage gastrointestinal stromal tumor

Gastrointestinal stromal tumors (GISTs) are rare but most common nonepithelial tumor of gastrointestinal tract. They are often found incidentally on computed tomography and endoscopic investigations. Increasing knowledge of the pathogenesis of GISTs and the advent of tyrosine kinase inhibitors revolutionized the management of GISTs. The newer advanced endoscopic techniques have challenged the conventional surgery although the true efficacy and safety of endoscopic approach is not clear at this time. This review article focuses on pathogenesis, diagnosis and management of GISTs.

Targeting gastrointestinal stromal tumors: the role of regorafenib

Gastrointestinal stromal tumor (GIST) is a devastating disease in the metastatic setting, but its natural history has been dramatically altered by the development of small molecule tyrosine kinase inhibitors, most notably imatinib. Although patients with advanced GIST live much longer today than they did in the past, imatinib-refractory disease remains a tremendous problem. For disease that is refractory to imatinib and sunitinib, regorafenib is an excellent option. In this review, we discuss the biology and clinical work establishing regorafenib as the standard of care for advanced GIST refractory to both imatinib and sunitinib.

Metastatic Gastrointestinal Stromal Tumor to the Skull

BACKGROUND

Gastrointestinal stromal tumors (GISTs) arising from the interstitial cells of Cajal along the gastrointestinal tract rarely metastasize to the central nervous system (CNS) but require aggressive multimodal therapies when they do. We present a case of recurrent GIST metastasis to the skull and review the literature on management, including the role of molecular profiling in determining adjuvant treatment.

CASE

A 64-year-old woman presented with an enlarging palpable mass over her right eye. Magnetic resonance imaging revealed an enhancing T1-hypointense, T2-hyperintense right frontal calvarial lesion with lytic features on computed tomography. Pathology confirmed metastatic GIST to the skull with dural involvement. Molecular profiling revealed a mutation in exon 11 of KIT in her primary tumor, while the skull metastasis harbored an additional mutation in exon 17 associated with acquired drug resistance.

CONCLUSION

We review the epidemiology of GIST metastases and discuss potential reasons for its rare presentation to the CNS. Additionally, we highlight the diagnostic and prognostic value of molecular profiling for metastatic GIST, as well as its influence in arbitrating targeted molecular inhibitor therapy. Evolving molecular signatures, associated with treatment resistance, may play a pivotal role in future integration with multimodality treatment strategies for CNS GIST.

Laparoscopic resection of large gastric GISTs: feasibility and long-term results

BACKGROUND

Laparoscopy is the procedure of choice for the resection of gastric Gastrointestinal stromal tumors (GISTs) smaller than 2 cm; there is still debate regarding the most appropriate operative approach for larger GISTs. The aims of this study were to evaluate the safety and long-term efficacy of laparoscopic resection of gastric GISTs larger than 2 cm.

METHODS

Between 2007 and 2011, we prospectively enrolled all patients affected by gastric GIST larger than 2 cm. Exclusion criteria for the laparoscopic approach were the presence of metastases and the absence of any involvement of the esophago-gastric junction, the pyloric canal, or any adjacent organ. Final diagnosis of GIST was confirmed by histological and immunohistochemical analysis. Follow-up assessment included abdominal CT scans every 6 months for the first 2 years and yearly thereafter.

RESULTS

Twenty-four consecutive patients were enrolled. Twenty-one patients (87.5%) were symptomatic. The most common symptoms were gastrointestinal bleeding and abdominal pain. The mean tumor size was 5.51 cm (range 2.5-12.0 cm). GISTs were located in the lesser curvature in five cases (20.8%), in the greater curvature in seven cases (29.1%), in the posterior wall in one case (4.1%), in the anterior wall in eight cases (33.3%), and in the fundus in 3 cases (12.5%). Laparoscopic resection was possible in all cases and took on average of 55 min (range 30-105 min). Median blood loss was 24 ml. No major intraoperative complications were observed. Mortality rate was 0%. Median postoperative stay was 3 days. No patients were lost to follow-up. No recurrences occurred after a median follow-up period of 75 months.

CONCLUSION

Although larger randomized controlled trials comparing different surgical strategies for large gastric GISTs are warranted, our study supports the evidence that laparoscopic resection of gastric GISTs is feasible, safe, and effective on long-term clinical outcome even for lesions up to 12 cm.

Endoscopy dissection of small stromal tumors emerged from the muscularis propria in the upper gastrointestinal tract: Preliminary study

AIM: To investigate the feasibility and safety of the treatment of an upper gastrointestinal (GI) submucosal tumor with endoscopic submucosal dissection (ESD).

METHODS: A total of 20 patients with esophageal and gastric submucosal tumors emerged from the muscular layer identified by endoscopic ultrasonography were collected from January 2009 to June 2010. Extramural or dumbbell-like lesions were excluded by an enhanced computerized tomography (CT) scan. All patients had intravenous anesthesia with propofol and then underwent the ESD procedure to resect these submucosal tumors. The incision was closed by clips as much as possible to decrease complications, such as bleeding or perforation, after resection of the tumor. All the specimens were collected and evaluated by hematoxylin, eosin and immunohistochemical staining, with antibodies against CD117, CD34, desmin, α-smooth muscle actin and vimentin to identify the characteristics of the tumors. Fletch’s criteria was used to evaluate the risk of gastrointestinal stromal tumors (GISTs). All patients underwent a follow-up endoscopy at 3, 6 and 12 mo and CT scan at 6 and 12 mo.

RESULTS: The study group consisted of 5 men and 15 women aged 45-73 years, with a mean age of 60.2 years. Three tumors were located in the esophagus, 9 in the gastric corpus, 4 in the gastric fundus, 3 lesions in the gastric antrum and 1 in the gastric angulus. Apart from the one case in the gastric angulus which was abandoned due to being deeply located in the serosa, 94.7% (18/19) achieved complete gross dissection by ESD with operation duration of 60.52 ± 30.32 min. The average maximum diameter of tumor was 14.8 ± 7.6 mm, with a range of 6 to 30 mm, and another lesion was ligated by an endoscopic ligator after most of the lesion was dissected. After pathological and immunohistochemical analysis, 12 tumors were identified as a GI stromal tumor and 6 were leiomyoma. Mitotic count of all 12 GIST lesions was fewer than 5 per 50 HPF and all lesions were at very low (9/12, 75.0%) or low risk (3/12, 25.0%) according to Fletch’s criteria. Procedure complications mainly included perforation and GI bleeding; perforation occurred in 1 patient and conservative treatment succeeded by a suturing clip and no post-operative GI bleeding occurred. All patients were followed up for 6.5 ± 1.8 mo (range, 3-12 mo) by endoscopy and abdominal CT. Local recurrence and metastasis did not occur in any patient.

CONCLUSION: ESD shows promise as a safe and feasible technique to resect esophageal and gastric submucosal tumors and the incidence of complications was very low. Clinical studies with more subjects and longer follow-up are needed to confirm its treatment value.

Primary extragastrointestinal stromal tumor arising in the pancreas: report of a case

Primary extragastrointestinal stromal tumors (EGISTs) arising in the pancreas are extremely rare, with only ten cases documented to our knowledge. We report a further case of EGIST of the pancreas. The patient was a 55-year-old man who presented with postprandial abdominal discomfort. Abdominal computed tomography and magnetic resonance imaging showed a lobulated heterogenous enhancing mass, 11 cm in diameter, in the abdominal cavity. No regional lymphadenopathy, ascites, or metastasis was seen radiologically. There was no obvious lesion in the stomach or small intestine. The initial diagnosis was a solid pseudopapillary tumor or serous cystic neoplasm. The patient underwent distal pancreatectomy with splenectomy. Microscopically, the tumor consisted of spindle cells arranged in short fascicles. Mitotic figures were seen in 7/50 high-power fields. Immunohistochemical examination revealed strongly positive staining for CD117. Based on these findings, the final pathologic diagnosis was a primary EGIST of the pancreas. This case consolidates the possibility that this rare tumor can involve the pancreas as a primary site and should be included in the differential diagnosis of cystic lesions in this site.

Tumor estromal gastrointestinal: análise de 146 casos do centro de referência do Instituto Nacional do Câncer - INCA

OBJETIVO: Avaliar os resultados do tratamento de GIST no INCA. MÉTODOS: Análise retrospectiva de todos os casos de GIST tratados no INCA no período de 1997 a 2009. RESULTADOS: Analisamos 146 pacientes, com média de idade de 44,5 anos e predomínio do sexo feminino. O principal sintoma foi dor abdominal. Tivemos ocorrência de segundo primário em 22% dos casos e na imuno-histoquímica, 92% foram positivos para CD117. A localização mais frequente foi estômago e predominou o grupo de alto risco. A cirurgia foi R0 (extenso) em 70% e os principais sítios de metástases foram fígado e peritônio. A sobrevida global foi, respectivamente, em dois e cinco anos de 86% e 59%. Houve significante diferença entre a sobrevida global (p=0,29) do grupo de alto risco versus os demais. CONCLUSÃO: Os nossos pacientes apresentam-se principalmente sob forma de doença de alto risco com repercussão óbvia na sobrevida. O uso de Imatinib melhorou a sobrevida dos pacientes com doença metastática e recidivada. Devemos estudar seu uso no cenário de adjuvância e neoadjuvancia visando melhorar os índices do grupo de alto risco. A criação de centros referenciais é uma necessidade para o estudo de doenças pouco frequentes.

GIST with a twist--upregulation of PDGF-B resulting in metachronous gastrointestinal stromal tumor and dermatofibrosarcoma protuberans

CASE REPORT

A 61-year-old male was referred following an incidental radiological discovery of an intra-abdominal mass. His medical history included excision of a lumbar dermatofibrosarcoma protuberans (DFSP) 5 years previously. A CT scan of the abdomen revealed a mass arising from the greater curvature of the stomach. Upper GI endoscopy was normal. He underwent successful laparoscopic resection of this mass.

MATERIALS AND METHODS

The histology of the abdominal mass revealed a gastrointestinal stromal tumor (GIST) with poor prognostic indicators. Immunohistochemical analysis of the GIST and his previous DFSP was performed.

RESULTS

Immunohistochemistry suggested a link between the GIST and his previous DFSP involving the PDGF signalling system.

DISCUSSION

Both GIST and DFSP are extremely rare tumors. A mutation in the platelet-derived growth factor receptor alpha (PDGFR-alpha) has been described in 5-15% of GISTs. It has been shown that DFSP is frequently associated with a translocation between PDGF-B (Chr 22) and COL1A1 (Chr 17), causing continuous activation of PDGFR-beta. Literature review confirms that there are no previously reported cases of both of these tumors occurring in the same patient.

CONCLUSION

We hypothesize that this patient may have a previously undescribed genetic mutation involving the PDGF signalling system, resulting in these two very rare malignancies. Immunohistochemistry studies confirmed the link on this occasion. Improvements in our understanding of the molecular biology of the PDGF system may novel therapeutic targets in the future.

Prognostic factors for survival in patients with epithelioid sarcoma: 441 cases from the SEER database

Current stratification of prognosis in patients with epithelioid sarcoma (ES) is based largely on data reported by individual centers with a limited number of patients. We sought to identify the important prognostic parameters using the Surveillance, Epidemiology, and End Results (SEER) database. We identified 441 patients with ES in the database and extracted information regarding patient demographics and clinical characteristics. Kaplan-Meier, log-rank, and Cox regression were used for analysis. Disease-specific survival declined until 100 months after diagnosis after which survival was unrelated to epithelioid sarcoma. The overall incidence of ES during 2005 was 0.041 per 100,000. The reported incidence has increased since 1973, with an annual percentage change of 5.217%. On multivariate analysis, only age younger than 16 years, local stage of disease, or negative nodes and surgical resection of the tumor predicted better disease-specific survival. We observed no increase in survival by comparing decades of diagnosis since 1986. The SEER database shows only age younger than 16 years, negative nodes, or local stage of disease and operability of primary disease independently predict survival in patients with ES.

LEVEL OF EVIDENCE

Level II, prognostic study. See Guidelines for Authors for a complete description of levels of evidence.

Ewing sarcoma demonstrates racial disparities in incidence-related and sex-related differences in outcome: an analysis of 1631 cases from the SEER database, 1973-2005

BACKGROUND

Previous reports of Ewing sarcoma cohorts suggested that there is a difference in incidence according to racial origin. However, to the authors' knowledge, this finding has never been tested in a population-based database, and the impact of race on clinical outcome and the significance of known risk factors stratified to racial groups have not been reported.

METHODS

Patients who had Ewing sarcoma diagnosed between 1973 and 2005 were identified in the Surveillance, Epidemiology, and End Results database. Patient demographic and clinical characteristics; incidence; year of diagnosis; tumor location, tumor size, and disease stage at diagnosis; treatment(s); cause of death; and survival were extracted. Kaplan-Meier, log-rank, and Cox regressions were used to analyze the significance of prognostic factors.

RESULTS

Race-specific incidence indicated that Caucasians have the highest incidence (0.155), followed by Asians/Pacific Islanders (0.082), and African Americans (0.017). The difference in incidence between Caucasians and African Americans was 9-fold and significant (P<.001). The incidence of Ewing sarcoma increased over the past 3 decades among Caucasians (P<.05). Survival was not impacted by race. Local disease stage, primary tumor location in the appendicular skeleton, and tumor size

CONCLUSIONS

To the authors' knowledge, this is the first report focusing on racial disparity in incidence of Ewing sarcoma. Caucasians were affected more frequently, although outcomes were similar between races. It is noteworthy that being a woman constituted a survival benefit only among the Caucasian patients. Further studies will need to clarify the reasons for racial disparities in incidence and for sex differences in survival.

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MESH Headings

• Adolescent
• Adult
• Black People
• Bone Neoplasms/epidemiology
• Bone Neoplasms/ethnology
• Bone Neoplasms/mortality
• Child
• Child, Preschool
• Female
• Hispanic or Latino
• Humans
• Incidence
• Infant
• Infant, Newborn
• Middle Aged
• Prognosis
• Racial Groups
• Risk Factors
• SEER Program
• Sarcoma, Ewing/epidemiology
• Sarcoma, Ewing/ethnology
• Sarcoma, Ewing/mortality
• Sex Distribution
• White People
• Black or African American

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Affiliation(s)

Muhammad U Jawad Department of Orthopedics, University of Miami Miller School of Medicine, Miami, Florida 33136, USA
Michael C Cheung
Elijah S Min
Michaela M Schneiderbauer
Leonidas G Koniaris
Sean P Scully

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Gastrointestinal stromal tumors and neuroendocrine tumors

OBJECTIVES

Patients with rare gastrointestinal (GI) malignancies can exhibit unique objective and subjective manifestations. This article is a primer for the fundamental understanding of some of these diseases, namely gastrointestinal stromal tumors (GIST) and gastroenteropancreatic neuroendocrine tumors (NET) and therapeutic strategies.

DATA SOURCES

Epidemiologic data, published research reports, national guidelines for oncology practice, and personal experience.

CONCLUSION

Despite the rarity of GIST, gastroenteropancreatic neuroendocrine tumors, gastric lymphoma, and adenocarcinoma of the small bowel, oncology nurses must be prepared to effectively assess, plan, and implement care strategies for these patients.

IMPLICATIONS FOR NURSING PRACTICE

Caring for patients with uncommon GI malignancies is challenging for oncology nurses whose experience with these tumors is limited. Fundamental knowledge and awareness of resources can help to ensure optimal patient care. Case vignettes illustrate patient presentation and formulation of treatment recommendations.

Outcomes of malignant CNS ependymomas: an examination of 2408 cases through the Surveillance, Epidemiology, and End Results (SEER) database (1973-2005)

BACKGROUND

Determine the role of surgery and radiation therapy for patients with malignant CNS ependymomas.

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database (1973-2005) was queried.

RESULTS

Overall, a total of 2408 cases of malignant ependymomas were identified. Of these, 2132 cases (88.5%) were identified as WHO grade II ependymomas and 276 cases (11.5%) as WHO grade III (anaplastic) ependymomas. The annual incidence of ependymomas was approximately 1.97 cases per million in 2005. Overall median survival for all patients was 230 mo, with a significant difference between women and men (262 mo versus196 mo, respectively) (P=0.004). Median age at diagnosis was 37 y among females and 34 y in males. Patients who successfully underwent surgical resection had a considerably longer median survival (237 mo versus 215 mo, P<0.001) as well as a significantly improved five-year survival (72.4% versus 52.6%, P<0.001). Univariate analysis demonstrated that age, gender, ethnicity, primary tumor site, WHO grade and surgical resection were significant predictors of improved survival for ependymoma patients. Multivariate analysis identified that a WHO grade III tumor, male gender, patient age, intracranial tumor locations and failure to undergo surgical resection were independent predictors of poorer outcomes. Multivariate analysis of partially resection cases revealed that lack of radiation was a sign of poor prognosis (HR 1.748, P=0.024).

CONCLUSION

Surgical extirpation of ependymomas is associated with significantly improved patient survival. For partially resected tumors, radiation therapy provides significant survival benefit.

Hepatic resection for gastrointestinal stromal tumor liver metastases

Liver resection is the preferred treatment for gastrointestinal stromal tumor liver metastases (GIST LMs) when complete resection can be achieved. Major and extended hepatic resections can be safely performed, and using modern techniques, an increasing proportion of patients with GIST LMs are candidates for potentially curative therapy. The combination of tyrosine kinase inhibitor therapy (eg, imatinib) with surgery seems to improve outcome, and although prospective data are lacking, a short neoadjuvant course (6 months) of imatinib therapy followed by resection may improve patient selection for surgery and outcome from treatment. Postoperative therapy with imatinib is generally advised, although the duration of such therapy is not yet clearly defined. These questions may formulate the basis for future prospective studies of imatinib with complete resection of GIST LMs.

Stage and histological grade of gastrointestinal stromal tumors based on a new approach are strongly associated with clinical behaviors

Tumor stage and grade for gastrointestinal stromal tumors are poorly defined. To develop a better evaluation system, we assessed 12 clinical and pathological parameters in 613 patients with follow-up information. These parameters were classified into two gross spread parameters including liver metastasis and peritoneal dissemination, five microscopic spread parameters including lymph node metastasis, vascular, fat, nerve and mucosal infiltration, and five histological parameters including mitotic count > or =10 per 50 high-power fields, muscularis propria infiltration, coagulative necrosis, perivascular pattern and severe nuclear atypia. The 5-year disease-free survival and overall survival of 293 patients without any of these predictive parameters of malignancy were 99 and 100%, respectively. They were regarded as nonmalignant and further evaluations on the stage and grade of these tumors were not performed. At least one and at most seven predictive parameters of malignancy were identified in 320 patients. For these patients, the 5-year disease-free survival and overall survival rates were 44% (mean 6.7 years) and 60% (mean 9.3 years), respectively. The disease-free survival showed significant difference between patients with and without gross spread (P<0.0001), with and without microscopic spread (P=0.0009). Disease-free survival and overall survival were associated with the number of predictive parameters of malignancy in patients without gross spread (P<0.0001 for both disease-free survival and overall survival), but not in patients with gross spread (P=0.882 and 0.441, respectively). Malignant gastrointestinal stromal tumors could be divided into clinical stage I and II based on the absence and presence of gross spread, respectively. The degree of malignancy of patients in clinical stage I could be graded according to the number of predictive parameters of malignancy. Patients in clinical stage II were of the highest degree of malignancy regardless of the number of parameters. We found that the clinical stage and grade were strongly associated with prognosis.

Malignant abdominal mesothelioma: defining the role of surgery

OBJECTIVE

Determine the role of surgery for patients with malignant abdominal mesotheliomas (MAMs).

METHODS

The Surveillance, Epidemiology, and End Results (SEER) database (1973-2005) was queried.

RESULTS

Overall, 10,589 cases of malignant mesotheliomas were identified. Of these, 9,211 cases were thoracic (TM) and 1,112 cases were MAM (10.5%). Patients with TM presented with more localized disease than those patients with MAM (P < 0.001). MAM more often affected younger patients (63 years vs. 71 years) (P < 0.001). The annual incidence of MAM was approximately 1.00 case per 100,000 in 2005. Overall median survival for MAM patients was 8 months, with a significant difference between women and men (13 months vs. 6 months, respectively) (P < 0.001). Patients who successfully underwent surgical resection had a considerably longer median survival (20 months vs. 4 months, P < 0.001) as well as a significantly higher 5-year survival (28% vs. 12%, P < 0.001). Multivariate analysis identified that a poorly differentiated tumor grade, failure to undertake surgical resection, advanced age, and male gender were all independent predictors of poorer outcome.

CONCLUSION

Surgical extirpation of MAM may be associated with significantly improved survival. All patients with MAM should be evaluated for potential surgical resection.

Prevalence and Management of Gastrointestinal Stromal Tumors

The prevalence and characteristics of patients with confirmed gastrointestinal stromal tumor (GIST) in a community hospital over a 6-year period are described. Our objective was to communicate our experience managing this rare tumor of the gastrointestinal tract. A retrospective chart review was performed. Patients were selected based on International Classification of Diseases, 9th Revision codes in correlation with their respective confirmational pathology. Patients with a diagnosis of GIST, cells of Cajal tumor, and/or different varieties of gastrointestinal sarcoma were included in this study. These tumors had to have a positive C-kit on immunohistochemistry. Demographic and clinical data were collected from medical records as well as pathology reports. Follow up from attendings’ office records and telephone interviews complemented our data. A total of 61 patients was identified in our institution (averaging 10 patients per year). Females represented 63 per cent of our series. The average ages were 70.2 ± 19.1 years for females and 59.4 ± 13.5 years for males ( P < 0.01). The most common clinical presentation was an intra-abdominal nonobstructing mass followed by an endoscopically detected mass or incidental tumors found during unrelated surgery. Surgical emergencies such as acute abdomen and gastrointestinal bleed were rare. Over half of these tumors were located in the stomach. Other sites were the small intestine, colon, esophagus, and rectal–vaginal septum. Opened surgical resection was performed in two-thirds of treated cases, whereas laparoscopic resection was done in the remainder. Only 18 per cent of these tumors were considered benign, whereas 35 per cent were considered to have some malignant potential and 47 per cent were of undetermined potential. In surgically resected tumors, we found a 42 per cent recurrence rate with a median average time of recurrence of 22 months. Pathologic grading and type of surgery were not predictors of rate and timing of recurrence. However, the disease tended to be more aggressive in white males and age older than 70 years. Imatinib was used mainly in attempts to downstage, control recurrent disease, and make surgery possible. With the improvement of immunohistochemical techniques, the diagnosis of GIST is increasing. Preoperative diagnosis is highly uncertain and dependent on clinical suspicion. Surgical resection is still the main form of curative therapy. Our experience is similar to large-volume centers. GIST, once recognized, can be treated in community hospitals without compromise of their care.

Gastrointestinal stromal tumors: key to diagnosis and choice of therapy

The common feature of gastrointestinal stromal tumors (GISTs) is the expression of KIT protein or acquisition of activating, constitutive mutations in the KIT or platelet-derived growth factor receptor alpha (PDGFRA) genes that are the early oncogenic events during GIST development. With these discoveries, GIST has emerged as a distinct sarcoma entity, enabling the introduction of targeted therapy using the inhibition of KIT/PDGFRA and their downstream signaling cascade. The introduction of a small-molecule tyrosine kinase inhibitor, imatinib mesylate, to clinical practice has revolutionized the treatment of patients with advanced GISTs and is currently approved as first-line treatment for patients with metastatic and/or inoperable GISTs. Mutation screening is currently a tool in GIST diagnosis, assessment of sensitivity to tyrosine kinase inhibitors, and prediction of achieving response to molecularly targeted therapy. This article discusses the histologic and molecular criteria for distinguishing GISTs from other types of sarcoma, and the molecular diagnostic tools that are currently available or in development to assist in therapy decisions.

Small Molecules: Big Changes in the Cancer Treatment Paradigm

Small molecules, a growing class of targeted therapies, have flourished over the last decade. With increased knowledge on molecular cell signaling, targeted therapy has been refined to targeting molecular targets upstream from the nucleus that are key players in the communication system that regulates cancer cell growth. This article reviews the mechanisms of small molecules with a particular emphasis on tyrosine kinase inhibitors, as well as the literature that supports the current clinical use in the treatment of a variety of solid and hematological malignancies.

Tumor estromal gastrointestinal: análise de fatores relacionados ao prognóstico

OBJETIVO: estudar os critérios morfológicos e imunoistoquímicos relacionados ao prognóstico dos tumores estromais gastrointestinais. MÉTODOS: o estudo foi retrospectivo de 42 casos de tumor estromal gastrointestinal (GIST). Vinte e cinco casos foram obtidos no arquivo do Serviço de Anatomia Patológica do Hospital Universitário Gaffrée e Guinle e os outros dezessete, do Serviço de Anatomia Patológica do Hospital Universitário Clementino Fraga Filho. RESULTADOS: de acordo com a análise univariada os tumores maiores que 5 cm, com número de mitoses maior que 5/50 CGA, presença de necrose, de alto risco, revelaram significância em relação a redução da sobrevida (p= 0,017, 0,010, 0,001 e 0,016, respectivamente). Os outros fatores analisados (subtipo histológico, topografia e imunofenótipo) não mostraram significância. CONCLUSÃO: os resultados confirmam a utilidade do grau de risco, do tamanho tumoral, do índice mitótico e da necrose como fatores preditores do comportamento biológico dos tumores estromais gastrointestinais.